Heparan sulfate proteoglycan 2(HSPG2)gene encodes the matrix protein Perlecan,and genetic inactivation of this gene creates mice that are embryonic lethal with severe neural tube defects(NTDs).We discovered rare genet...Heparan sulfate proteoglycan 2(HSPG2)gene encodes the matrix protein Perlecan,and genetic inactivation of this gene creates mice that are embryonic lethal with severe neural tube defects(NTDs).We discovered rare genetic variants of HSPG2 in 10%cases compared to only 4%in controls among a cohort of 369 NTDs.Endorepellin,a peptide cleaved from the domain V of Perlecan,is known to promote angiogenesis and autophagy in endothelial cells.The roles of enderepellin in neurodevelopment remain unclear so far.Our study revealed that endorepellin can migrate to the neuroepithelial cells and then be recognized and bind with the neuroepithelia receptor neurexin in vivo.Through the endocytic pathway,the interaction of endorepellin and neurexin physiologically triggers autophagy and appropriately modulates the differentiation of neural stem cells into neurons as a blocker,which is necessary for normal neural tube closure.We created knock-in(KI)mouse models with human-derived HSPG2 variants,using sperm-like stem cells that had been genetically edited by CRISPR/Cas9.We realized that any HSPG2 variants that affected the function of endorepellin were considered pathogenic causal variants for human NTDs given that the severe NTD phenotypes exhibited by these KI embryos occurred in a significantly higher response frequency compared to wildtype embryos.Our study provides a paradigm for effectively confirming pathogenic mutations in other genetic diseases.Furthermore,we demonstrated that using autophagy inhibitors at a cellular level can repress neuronal differentiation.Therefore,autophagy agonists may prevent NTDs resulting from failed autophagy maintenance and neuronal over-differentiation caused by deleterious endorepellin variants.展开更多
This study investigated the inhibitory effect of a high efficiency diuretic, furosemide, on carbonic anhydrase （CA）. First, comparing the inhibitory effect of acetazolamide, a low efficiency diuretic, on CA, shows t...This study investigated the inhibitory effect of a high efficiency diuretic, furosemide, on carbonic anhydrase （CA）. First, comparing the inhibitory effect of acetazolamide, a low efficiency diuretic, on CA, shows that furosemide or acetazolamide can quickly make CA inactive when its concentration is close to the enzyme concentration, different from the usual inhibitory kinetics in which the concentration of the inhibitor is far higher than the enzyme concentration. Secondly, the reaction of the enzyme indicates that the inhibitory effect of furosemide or acetazolamide on carbonic anhydrase is quickly reversible. Finally, the degree of the inhibitory effect of furosemide and of acetazolamide on CA are compared. The results show that furosemide inhibits CA less than acetazolamide.展开更多
基金supported by the National Key Research and Development Program of China(2021YFC2701100)the National Natural Science Foundation of China(81930036,32293230 and 8215008)+1 种基金the Commission for Science and Technology of Shanghai Municipality(20JC1418500 and 20ZR1404800)Project supported by Shanghai Municipal Science and Technology Major Project。
文摘Heparan sulfate proteoglycan 2(HSPG2)gene encodes the matrix protein Perlecan,and genetic inactivation of this gene creates mice that are embryonic lethal with severe neural tube defects(NTDs).We discovered rare genetic variants of HSPG2 in 10%cases compared to only 4%in controls among a cohort of 369 NTDs.Endorepellin,a peptide cleaved from the domain V of Perlecan,is known to promote angiogenesis and autophagy in endothelial cells.The roles of enderepellin in neurodevelopment remain unclear so far.Our study revealed that endorepellin can migrate to the neuroepithelial cells and then be recognized and bind with the neuroepithelia receptor neurexin in vivo.Through the endocytic pathway,the interaction of endorepellin and neurexin physiologically triggers autophagy and appropriately modulates the differentiation of neural stem cells into neurons as a blocker,which is necessary for normal neural tube closure.We created knock-in(KI)mouse models with human-derived HSPG2 variants,using sperm-like stem cells that had been genetically edited by CRISPR/Cas9.We realized that any HSPG2 variants that affected the function of endorepellin were considered pathogenic causal variants for human NTDs given that the severe NTD phenotypes exhibited by these KI embryos occurred in a significantly higher response frequency compared to wildtype embryos.Our study provides a paradigm for effectively confirming pathogenic mutations in other genetic diseases.Furthermore,we demonstrated that using autophagy inhibitors at a cellular level can repress neuronal differentiation.Therefore,autophagy agonists may prevent NTDs resulting from failed autophagy maintenance and neuronal over-differentiation caused by deleterious endorepellin variants.
文摘This study investigated the inhibitory effect of a high efficiency diuretic, furosemide, on carbonic anhydrase （CA）. First, comparing the inhibitory effect of acetazolamide, a low efficiency diuretic, on CA, shows that furosemide or acetazolamide can quickly make CA inactive when its concentration is close to the enzyme concentration, different from the usual inhibitory kinetics in which the concentration of the inhibitor is far higher than the enzyme concentration. Secondly, the reaction of the enzyme indicates that the inhibitory effect of furosemide or acetazolamide on carbonic anhydrase is quickly reversible. Finally, the degree of the inhibitory effect of furosemide and of acetazolamide on CA are compared. The results show that furosemide inhibits CA less than acetazolamide.
